Rock drill bit



S. F. SPENCER ROCK DRILL BIT Feb. 14, 1961 Filed Aug. 22, 1958 INVENTOR. 5267/072f128e726eg BY %%W)@WM film United States PatehtO nocx DRILL BIT Sherron F. Spencer, Mancos, Colo., assignor to Spencer Rock Drill Co., Inc., Mancos, Colo., a corporation of Colorado Filed Aug. 22, 1958, Ser. No. 756,621

2 Claims. 01. 115-400 The present invention relates in general to drilling tools and in particular to a rock drill bit for cutting by percussive impact and rotative forces.

An object of the present invention is to provide a rock bit which lends itself to efficient and rapid drilling of rock with fast removal of chips and dust from the hole being drilled.

Another object of the present invention is to provide a rock drill bit which has means enabling the operator to drill out without the bit binding or locking in the hole.

A further object of the present invention is to provide a rock drill bit which has means eliminating drag on drilling and therefore allowing faster cutting and enabling the operator to employ the drill for longer drilling operations between resharpening or replacement of the drill bit.

These and other objects and advantages of the present invention will be fully apparent from the following description when taken in conjunction with the annexed drawing, in which:

Figure 1 is an elevational view of the drill bit of the present invention;

Figure 2 is another elevational view taken on a 45 degree angle from Figure 1;

Figure 3 is a bottom plan view;

Figure 4 is a top plan view; and

Figure 5 is a view taken on the line 5-5 of Figure 3.

Referring in greater detail to the drawing in which like numerals indicate like parts throughout the several views, the rock drill bit of the present invention is designated generally by the reference numeral and comprises an upstanding cylindrical body 12 having a plurality of upstanding wings 14, 16, 18, and 20 adjacent one end of the body.

The wings 14, 16, 18, and 20 radiate from the longitudinal axis of the body 12 and each wing has a side edge and a side face, as at 17 and 44 respectively, with respect to the wing 20 of Figure 2, spaced outwardly from the perimeter of the body 12.

The lower end of each of the wings 14, 16, 18, and 20 is shaped to a main cutting edge 22, 24, 26, and 28, respectively, each embodying a pair of inclined leading and trailing surfaces 21 and 23, respectively, as shown in Figure 3 with respect to the cutting edge 24 of wing 16. The surfaces 21 and 23 of each wing extend in a diverging direction upwardly toward the wing. The cutting edges 22, 24. 26, and 28 are disposed in cruciform shape. The inner ends of the radially-arranged cutting edges 22, 24, 26, and 28, terminate at the edge of a bore 30 which extends inwardly from the lower end of the body 2,971,594 Patented Feb. 14, 1 961 12 and terminates at a point adjacent the lower end of the body 12.

The Wings 14, 16, 18, and 20, are all formed identical and will be described with reference to the wing 14. The wing 14 has a front face 13 and a rear face 15. A shoulder 38 joins the front face 13 and the rear face 15. The junction of the front face 13 and side face 44 forms a side edge 17.

The front face of the wing 14 is provided with an upwardly-sloping channel 36 extending from the leading surface 21 of the main cutting edge 22 to the upper end of the wing 14. The junction of the inclined leading surface 21 of the main cutting edge 22 of the wing 14 with the side face 44 forms an auxiliary leading cutting edge 32. The junction of the side edge 17 of the wing 14 with the rear face 15 of the wing 14 forms a trailing edge 34.

Each wing projecting portion has a shoulder 38, shown to be flat in Figure 2, and extending from the upper end of the rear face 15 to the upper end of the channel 36.

The upper end of the body 12 is provided with another bore 40 extending inwardly from the upper end thereof and terminating at a point mid-way between the upper end of the body 12 and the lower end of the body 12. A passageway 42 is formed in the body 12 and has its upper end connected in communication with the bottom of the bore 40 and its lower end opening to the atmosphere in the space between the wings 16 and 18 in the concavely-curved part of the body 12 between the lower ends of the wings 16 and 18, as shown most clearly in Figures 3 and 5.

In use, the bit 10 is attached to the drill steel by receiving the end portion of the drill steel in the bore 40 which is of a size to provide a tight fit, as exemplified by the patent to Liddicoat No. 2,592,440, issued April 8, 1952. Upon application of a percussive impact and rotative force of the drill steel, the bit 10 will rotate in the direction in which the leading edge 32 of each of the wings 14, 16, 18, and 20, cuts into the rock being drilled while the main cutting edges 22, 24, 26, and 28, shatter the rock. Air under pressure admitted through the drill steel into the bore 40 and through the passageway 42 removes the chips and dust from the hole as it is being drilled. The undercut channel 36 on each of the wings 14, 16, 18, and 20, eliminates drag of the bit 10 as it is being rotated and enables an operator to efiiciently and rapidly drill holes in rock, slate, and other formations.

What is claimed is:

1. In a rock drill hit, an upstanding cylindrical body, a plurality of upstanding wings radiating from the longitudinal axis of said body, the lower end of each of said wings being shaped to a main cutting edge embodying a pair of inclined leading and trailing surfaces extending in a diverging direction upwardly from said cutting edge, each of said wings having a front face, a rear face, a side face, a shoulder joining said front and rear faces, the junction of said front and side faces forming a side edge, the main cutting edges being disposed in cruciform shape, there being an upwardly-sloping channel on the front face of each of said wings and extending from the inclined leading surface of the main cutting edge to the shoulder, the junction of the inclined leading surface of said main cutting edge of each wing and the adjacent side face forming a cutting leading edge.

2. In a rock drill hit, an upstanding cylindrical body,

front face of each of said wings and extending. from the inclined leading surface of the main cutting edge to the shoulder, the junction of the inclined leading surface of said main cutting edge of each wing and the adjacent side face forming a cutting leading edge, the junction of the side face with the rear face "of each 'wing forming a trailing edge.

References Cited in the file of this patent UNITED STATES PATENTS 1,670,896 Maickel et a1. May 22, 1928 2,294,004 Serafino Aug. 25, 1942 2,519,861 Turner Aug. 22, 1950 2,602,639 Green July 8, 1952 FOREIGN PATENTS 25,966 Great Britain L. Aug. 20, 1903 

